1. Field of the Invention
This invention is directed to both a method and system for testing roof sheathings. In particular, this invention relates to a roof sheathing test system and method which is manually operated and may be easily attached and removed from a roof being tested. Still further, this invention directs itself to a roof sheathing test system which allows fixed securement of a portion of the test system to the roof being tested while a test frame is removably secured for the operational tests. More in particular, this invention is directed to a system where a particular loading is applied to the sheathing of a roof for determination of the strength of the roof sheathing. Additionally, this invention is related to a system whereby the deflection at differing load values may be registered in a simple, economical manner during the operational phase of the testing. Further, this invention directs itself to a roof sheathing test system which tests according to the U.S. Product standards provided by the American Plywood Association Rules and Regulations. Further, this invention relates to a roof sheathing test system which may be easily brought to a test site to apply the operational test in an effective, low cost, non destructive, manner.
2. Prior Art
Test systems for measuring load and deflections are known in the art. The best prior art known to the Applicant includes U.S. Pat. Nos. 4,589,288; 4,213,349; 2,854,847; 4,747,314; 3,194,063; 3,533,283; 3,942,362; 3,041,873; 4,300,398; 4,543,126; 3,443,423; and, 4,289,047.
In some prior art, such as that shown in U.S. Pat. No. 4,589,288 there is provided a device for non-destructive testing of wood panels. In such prior art systems a force load is applied to a wood panel through a force applying assembly having a loading bar which is coupled thereto. The force applying assembly provides a known displacement to the panel by virtue of its predetermined stroke and a load cell provides monitoring of the applied force. However, such prior art systems do not provide for a simple and effective non-destructive load testing system where there is a combination of fixed securement to the roof truss members and a releasable securement to the test frame in the manner shown by the subject Patent Application system and method. Additionally, such prior art systems do not provide for the particular method and mode of operation whereby the force loading and the deflection of the sheathing may be provided during the test operation in the manner shown by the subject Patent Application system.
In other prior art systems, such as that shown in U.S. Pat. No. 4,213,349, there are testing machines to determine the stiffness of a test specimen. Such does provide a screw jack arrangement to apply force to a specimen under test and is measured by some type of dial gauge interposed therebetween. The force applying assembly may be supported by a pair of vertical legs in such prior art systems however the specimens are disposed between the force applying member and a crossbar which is not part of the combination of elements nor workable in the particular operational system as described herein.